Frontier Airlines just started 1-day promotion for flights from/to Chicago from various US cities. Tickets for 29 USD one way/58 USD round trip!
Mondays, Tuesdays, Wednesdays, Thursdays, Saturdays, September 22, 2014 through January 28, 2015.
Chicago – Atlanta/Cleveland/Denver/Washington/Orlando/Phoenix/Salt Lake City or to Chicago.
How to book: